The present invention relates to an electrical contact and an electrical connection device using the contact. Particularly, the present invention relates to an electrical contact formed by a metal injection molding or metallic powder injection molding method for electrically connecting a circuit board with an electrical connection device.
It is common to manufacture electrical contacts by stamping and forming metal. However, it is difficult to stamp and form tapered electrical contacts having a desired graded cross sections in two axes. If a die cast process is used, it becomes relatively easy to mold contacts having desired cross sectional shapes. However, in the die cast method, it is difficult to form small contacts, and problems arise with dimensional accuracy.
A manufacturing method that has been utilized to address these problems is known as a metal injection molding (MIM) method. The metal injection molding method, hereinafter referred to as MIM method, is a method in which metallic fine particle powder is plasticized with a thermoplastic binder, then injected into a metal mold of an injection molding machine to form a product having a desired shape. This method is suitable for mass production of metal products having comparatively complex three dimensional shapes.
As an example of the MIM method, Japanese Unexamined Patent Publication No. 5 (1993)-198225 discloses a circuit wiring member. This circuit wiring member has a conductive path formed as a plate frame, and a plurality of rectangular tab terminals protruding on both sides of the conductive path perpendicularly.
The tab terminals are formed normal to the conductive path such that the contact does not resile upon mating with a connecting member. Accordingly, it is not possible to establish an electrical connection through resilient contact by contacting the circuit wiring member with a circuit board, or by placing the circuit wiring member between two circuit boards and applying pressure to the tab terminals. In addition, the arrangement interval or pitch of the tab terminals is large, and the tabs terminals are not structured to be able to be arranged with high density.
It is an object of the present invention to provide an electrical connection device and an electrical contact which is extremely resilient for applications requiring a narrow pitch and electrical connection over a short electrical path.
It is another object of the present invention to provide an electrical contact having a high degree of freedom in the design of its shape, as well as an electrical connection device for such a contact.
An electrical contact of the present invention is an electrical contact constructed by molding a conductive metallic powder with a metal injection molding method. The contact having a base portion, a support, and an elastic arm that extends from the base portion through the support to an electrical contact portion.
The cross section of this arm may be made large in the vicinity of the base portion, and small at the distal end portion thereof.
An electrical connection device of the present invention features a plurality of the first, second, third, or fourth electrical contacts and a circuit board having the plurality of electrical contacts arranged on at least one side. The base portions of the plurality of electrical contacts are attached to the circuit board so that the plurality of electrical contacts are arranged on the circuit board as a matrix.